Field Calculators

Free estimating calculators built the way the material is actually sold — yards, tons, bags, boxes, sheets, board feet. Every formula is printed on the page with its assumptions, so you can check the math before you order.

Measuring & volume

Square Footage Calculator — rectangles, triangles, circles, trapezoids, and whole rooms.

Cubic Yard Calculator — length × width × depth into yards, feet, meters, and tons.

Feet & Inches Calculator — add, subtract, multiply, and divide tape measurements; fractions to the nearest 1/16.

Unit Conversion Calculator — length, area, volume, and weight, US and metric, with a reverse check.

Concrete Calculator — cubic yards plus 60 lb and 80 lb bag counts, waste included.

Bulk materials

Gravel Calculator — yards and tons, density printed on the page.

Sand Calculator — bedding and base sand: yards, tons, and 50 lb bags.

Asphalt Calculator — tons from compacted thickness at 142–148 lb per cubic foot.

Fill Dirt Calculator — grading and backfill with the compaction allowance in.

Topsoil Calculator — yards and 1.5 cu ft bags, settling counted.

Mulch Calculator — yards and 2 cu ft bags, with the depth guide.

Interiors & finishes

Tile & Grout Calculator — tile count with the joint in the math, plus grout and thinset.

Flooring Calculator — boxes to buy, waste set by install pattern.

Carpet Calculator — both run directions priced, pattern repeat and waste in, order by the lineal foot.

Drywall Calculator — sheets, screws, joint compound, and tape.

Roofing Calculator — squares and bundles from the roof footprint and pitch.

Paint Calculator — gallons with realistic coverage, one coat or two.

Lumber & masonry

Stud Calculator — wall studs with corners and openings counted, plates, lineal feet, and board feet.

Board Foot Calculator — board feet, lineal feet, and cost at your $/board-ft.

Brick Calculator — modular, queen, and king counts with mortar.

Concrete Block Calculator — 1.125 blocks per sq ft, mortar, and core fill.

Mortar Calculator — bags from a unit count, 60 or 80 lb.

Exterior & site

Decking Calculator — boards with the gap counted, joists, and fasteners.

Fencing Calculator — posts, rails, pickets, and concrete — gates out first.

Siding Calculator — squares, lap boards by exposure, panels, and boxes.

Retaining Wall Calculator — blocks, caps, and gravel — quantity only, never design.

Paver Calculator — pavers, base, bedding, and joint sand in one take-off.

Gutter Calculator — sections, downspouts by both planning rules, elbows, hangers.

Sod Calculator — rolls and pallets from the farm coverage you enter.

Grass Seed Calculator — pounds and bags by grass type, new lawn or overseed.

Excavation Calculator — bank yards, loose yards after swell, and truckloads.

Driveway Cost Calculator — concrete vs asphalt vs gravel, install cost and cost per year of life.

Window & Door Cost Calculator — planning ranges from dated national presets you can override, disposal in.

Geometry & layout

Roof Pitch Calculator — x:12, angle, grade, and the roof-area multiplier.

Stair Calculator — risers, treads, run, and stringer — checked against IRC R311.7.

Slope Calculator — percent, ratio, degrees, and fall per foot.

Drainage Slope Calculator — total drop over a run, presets labelled common practice.

Rafter Calculator — common rafter length with the ridge deduction done right.

Steel, sheet goods & coverings

Rebar Calculator — grid counts, stock bars, and weight — quantity only.

Steel Weight Calculator — plate, bar, tube, and angle by density.

Plywood Calculator — sheathing and subfloor sheets with waste.

Wallpaper Calculator — strips, repeat-matched drops, and rolls.

Insulation Calculator — depth for the R-value, units from the label coverage.

Home systems

Pipe Volume & Flow Calculator — gallons in the line and flow through it, from true inside diameter.

Ohm’s Law Calculator — volts, amps, ohms, and watts from any two.

Lighting Calculator — the lumen method: fixtures from foot-candles, CU, and LLF.

HVAC BTU Calculator — a preliminary load estimate with a ±15% range — an estimator, never a Manual J.

Solar Panel Calculator — how many panels your usage needs. Count and roof area only — no payback promises.

Battery Size Calculator — backup storage in kWh and amp-hours from your critical loads.

Insulation Savings Calculator — what an R-value upgrade saves a year, degree-day math, honest paybacks.

Generator Size Calculator — running watts plus the largest starting surge, from a load checklist.

Water Heater Size Calculator — tank size by first-hour rating, or tankless flow at your real temperature rise.

Attic Ventilation Calculator — net free area by the 1:150 / 1:300 rules, split intake and exhaust.

Go deeper

Questions from the field

How are the quantities figured? The calculators are built the way the material is actually sold — yards, tons, bags, boxes, sheets, board feet.

Can I check the math before I order? Yes. Every formula is printed on the page with its assumptions, so you can check the math before you order.

What kinds of calculators are here? Measuring and volume, bulk materials, interiors and finishes, lumber and masonry, exterior and site work, geometry and layout, steel and sheet goods, and home systems — from square footage and concrete to roof pitch, rebar, and HVAC sizing estimates.

Do these calculators replace design or engineering? No. The retaining wall and rebar calculators are quantity only, never design, and the HVAC BTU calculator is a preliminary load estimate with a ±15% range — an estimator, never a Manual J.

Does the solar calculator promise a payback? No. It gives a panel count and roof area only — no payback promises.

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